More than 70,000 people waving Russian flags and brandishing posters of President Vladimir Putin have taken to the streets in Simferopol, capital of the Crimean peninsula.

The marchers Thursday carried banners reading: "We are Russia" and "Putin is our president", said an AFP reporter on the scene.

Authorities said 75,000 people took part.

They appeared to be mainly public sector workers celebrating Labour Day, the reporter said.

Crimea broke away from Ukraine in March in a referendum that resulted in 97 percent of ballots backing Moscow rule.

"We are very worried by what we are seeing in eastern Ukraine. We cannot let the (Ukrainian) army shoot at civilians. All Russians should come together," said Vladimir Konstantinov, speaker of the Crimean parliament.

The east of the country is in the grip of a separatist movement that has seen pro- Moscow activists seize official buildings in more than a dozen towns and cities, sometimes using force.

In the port city of Sevastopol, home to Russia's Black Sea fleet, some 8,000 people took part in the May Day march, according to authorities.

Putin and Prime Minister Dmitry Medvedev are likely to make a rare joint trip to Crimea for a May 9 military parade marking victory in World War II in Sevastopol, Russian media have reported.